The Hanford 100 Area site covers 26 square miles, 35 miles north of Richland, Washington. It is one of four areas at the Hanford Nuclear Reservation (Hanford) originally listed on EPA's National Priorities List (NPL); the other three are the 200, 300, and 1100 Areas. These areas are part of a U.S. Department of Energy (DOE) complex which includes buildings, disposal sites, a national monument, and other vacant land totaling about 586 square miles.

Hanford was established in the 1940s to make plutonium for nuclear weapons. Since then the site mission has expanded to include other uses of nuclear materials, environmental cleanup, and research and development.

The 100 Area cleanup is focused on contamination that originated from nine nuclear reactors, the last one shutting down in 1988. Cooling water contaminated with radioactive and hazardous chemicals was discharged to both the adjacent Columbia River and infiltration cribs and trenches. Contaminated solid wastes were disposed of in burial grounds. Contaminated soil, solid wastes, and buildings are being removed to protect the environment and restore future beneficial uses. Approximately 11 square miles of groundwater are contaminated, primarily with chromium and radioactive elements. Groundwater is not currently used for drinking water; however, it does discharge into the Columbia River which is used by downstream communities for drinking water and other purposes. Groundwater contamination is addressed by source removals, pump-and-treat actions, and in-situ barriers.

Site Responsibility: This site is being addressed through federal and state actions.

NPL Listing History

Dates

Proposed Date:

06/24/1988

Removed Date:

Withdrawal Date:

Final Date:

10/04/1989

Deleted Date:

Threats and Contaminants

Media Affected:Soil & Sludges, GroundwaterSoils are contaminated with both radiological and chemical waste. Groundwater contains radioactive waste material, including strontium-90, carbon-14, and tritium. It also contains hexavalent chromium, which is particularly toxic to aquatic organisms where groundwater discharges into the Columbia River. People may be exposed to hazardous substances through direct contact or accidental ingestion of contaminated groundwater. The Columbia River traverses the 100 Area adjacent to the reactor areas and is the main source of water for downstream municipal supply systems. The metropolitian area which includes the cities of Richland, Pasco, and Kennewick, immediately downstream of Hanford and with a combined population of over 170,000, maintain water intakes on the Columbia River. Over half a million people live within 50 miles of Hanford.

Cleanup Progress

In May 1989, EPA, the State, and DOE entered into an Interagency Agreement and Consent Order to set up a process and legal framework for cleanup and regulatory compliance at Hanford. EPA, DOE, and the State developed an action plan addressing Superfund and Resource Conservation and Recovery Act (RCRA) issues. One final and numerous interim action remedies have been selected for essentially all the waste sites and all but two groundwater operable units. From 2000-2004, 2300 tons of spent nuclear material was removed. Over 7.37 million tons of contaminated soil and debris have been removed from the site’s waste areas since 1996 and disposed of in Hanford's 200 Area as of March 2010. Currently there are four active groundwater pump-and-treat systems for hexavalent chromium in the 100 Area designed to protect the Columbia River. Over 3.80 billion gallons of chromium-contaminated water has go through the pump and treat system and 1,176 kg of hexavalent chromium has been removed as of March 2010. DOE has installed a 2200 foot long in-situ barrier for hexavalent chromium-contaminated groundwater. During September 2006 and February-March 2007 DOE installed a 300 foot long in-situ barrier using appatite to treat radioactive Strontium-90 contaminated ground water.